Commit dcecdd3d authored by POTTIER Francois's avatar POTTIER Francois

A Q&A about speed.

parent d23f48ee
......@@ -258,7 +258,8 @@ is optional.
\docswitch{\otable} This switch causes \menhir to use its table-based
back-end, as opposed to its (default) code-based back-end. When \otable is
used, \menhir produces significantly more compact, slightly slower parsers.
used, \menhir produces significantly more compact and somewhat slower parsers.
See \sref{sec:qa} for a speed comparison.
The table-based back-end produces rather compact tables, which are analogous
to those produced by \yacc, \bison, or \ocamlyacc. These tables are not quite
......@@ -1849,6 +1850,18 @@ The list is roughly sorted by decreasing order of importance.
% ---------------------------------------------------------------------------------------------------------------------
\section{Questions and Answers}
\label{sec:qa}
$\mathstrut$ % Ensure correct indentation of the first question. Ugly.
\vspace{-\baselineskip}
\question{Is \menhir faster than \ocamlyacc? What is the speed difference
between \texttt{menhir} and \texttt{menhir -{}-table}?} A (not quite
scientific) benchmark suggests that the parsers produced by \ocamlyacc and
\texttt{menhir -{}-table} have comparable speed, whereas those produced by
\texttt{menhir} are between 2 and 4 times faster. This benchmark excludes the
time spent in the lexer and in the semantic actions.
\question{Turning on \oinfer broke my \Makefile! What should I do?}
Look at \distrib{demos/Makefile.shared}. It is meant to be re-used
......@@ -1874,6 +1887,7 @@ fact, to a simpler, revised API. In the revised API, there are no lexing
buffers, and a lexer is just a function from unit to tokens. Converters are
provided within \menhirlibconvert. This can be useful, for instance, for
users of \texttt{ulex}, the Unicode lexer generator.
% TEMPORARY the incremental interface does not mention lexbufs
% ---------------------------------------------------------------------------------------------------------------------
......
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